Valerie Harper – whose terminal brain cancer is close to remission – was named one of the 12 celebrities who will compete for the mirror ball when Dancing with the Stars returns Sept. 16 on ABC.

The former Mary Tyler Moore Show comedian, 74, announced in March that she was diagnosed with leptomeningeal carcinomatosis, a kind of cancer that attacks the membranes around the brain. But a recent MRI showed signs of hope for the actress – who was apparently quite eager to put on her dancing shoes again, Executive Producer Conrad Green tells EW.

“Her positivity is incredible. She’s very much about doing the things she wants to do, living life to the fullest,” he says. “She sees this as an opportunity to say to people who have a devastating illness that you can get up there and enjoy life, embrace it, and make the most of it. She loves to dance. She danced on Broadway 50 years ago. It’s about getting back to her passion.”

Here are rest of the celebrities (and the three new pros) who were announced this morning on ABC’s Good Morning America:

Since the 17th season will only air once a week to make way for the new drama Marvel’s Agents of S.H.I.E.L.D, the show will undergo some changes this fall. The celebraquarium, for example, will move next to the judges to free up co-host Brooke Burke (yup, she’s back!) to interview the couples before they perform. “We want to get a little more story of the night while it’s progressing,” says Green.

Live performances by musical guests will still occur even though there is no longer a results show, Green says; they’ll just happen later in the season. And look for some guest judges and “a few surprises along the way.”

As for the decision to include Harper, Green says the show approached the actress before she received her latest diagnosis from physicians. (Her doctor told Today last week that she’s pretty “close to remission.”) Unless she’s got some pretty fancy footwork, however, Green doesn’t think she’ll ride a wave of sympathy all the way to the finals. (Her partner will be Tristan MacManus).

“People vote for whatever reason they want to, but what tends to happen toward the end, over the last couple of weeks, is that the best dancers tend to come out,” he says. “If Valerie is a strong dancer, she’s got a strong chance of winning the show.”